lock-striping | Coarse Grained Synchronization vs Lock Striping https

by alimate Java Version: Current License: Apache-2.0

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kandi X-RAY | lock-striping Summary

lock-striping is a Java library. lock-striping has no bugs, it has no vulnerabilities, it has build file available, it has a Permissive License and it has low support. You can download it from GitHub.

A simple repository to demonstrate the fact that how well a fine-grained synchronized concurrent data structure performs compared to its coarse-grained counterpart.

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Support

lock-striping has a low active ecosystem.

It has 5 star(s) with 0 fork(s). There are 1 watchers for this library.

It had no major release in the last 6 months.

lock-striping has no issues reported. There are no pull requests.

It has a neutral sentiment in the developer community.

The latest version of lock-striping is current.

Quality

lock-striping has no bugs reported.

Security

lock-striping has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.

License

lock-striping is licensed under the Apache-2.0 License. This license is Permissive.

Permissive licenses have the least restrictions, and you can use them in most projects.

Reuse

lock-striping releases are not available. You will need to build from source code and install.

Build file is available. You can build the component from source.

Installation instructions are not available. Examples and code snippets are available.

Top functions reviewed by kandi - BETA

kandi has reviewed lock-striping and discovered the below as its top functions. This is intended to give you an instant insight into lock-striping implemented functionality, and help decide if they suit your requirements.

Resize buckets
Acquires all locks
Release all locks
Gets the value associated with the given key
This method generates a hash code for the given key
Find the bucket for the given entry
Benchmarks for a coarse grained executor
Perform a workload on the cluster
Tries to acquire a lock for the given entry
Returns the lock for the given entry
Adds an entry to the map
Attempts to release the lock for the given entry
Entry point
Benchmark for extracting lock
Acquires an entry
Unlock entry
Increases the size of the hash table
Compares this map with the specified key
Removes the specified key from the map
Returns a random key

Get all kandi verified functions for this library.

lock-striping Key Features

No Key Features are available at this moment for lock-striping.

lock-striping Examples and Code Snippets

No Code Snippets are available at this moment for lock-striping.

Community Discussions

Trending Discussions on lock-striping

Java 8+ ConcurrentHashMap lock striping

QUESTION

Java 8+ ConcurrentHashMap lock striping

Asked 2019-Aug-15 at 07:14

I have been reading through Concurency in Practice by Brian Goetz.

In the chapter about Lock Striping it is written that ConcurrentHashMap uses 16 buckets to improve multithreaded access by many threads :

Lock splitting can sometimes be extended to partition locking on a variablesized set of independent objects, in which case it is called lock striping. For example, the implementation of ConcurrentHashMap uses an array of 16 locks, each of which guards 1/16 of the hash buckets; bucket N is guarded by lock N mod 16.

I have read those questions :

ConcurrentHashMap locking

Need simple explanation how “lock striping” works with ConcurrentHashMap

However those answers are valid for Java version <= 7.

For Java 8+ the behaviour seems to be changed significantly. For Java 8+ it seems that that the lock is acquired not for a Segment but for particular Node in table (transient volatile ConcurrentHashMap.Node[] table;). For example for the putVal operation :

...

ANSWER

Answered 2019-Jul-28 at 10:35

What is the cause of such significant change in ConcurrentHashMap implementation?

To reduce memory footprint (one of the reasons).

We do not want to waste the space required to associate a distinct lock object with each bin, so instead use the first node of a bin list itself as a lock. Locking support for these locks relies on builtin "synchronized" monitors.

^{openjdk > jdk8 > java.util.concurrent.ConcurrentHashMap.java > Line 314}

If class Segment is unused and also field like DEFAULT_CONCURRENCY_LEVEL is also unused - why not get rid of it from implementation - is it for some historical reasons?

To ensure serialization compatibility.

We also declare an unused Segment class that is instantiated in minimal form only when serializing.

^{openjdk > jdk8 > java.util.concurrent.ConcurrentHashMap.java > Line 486}

Source https://stackoverflow.com/questions/57239419

Community Discussions, Code Snippets contain sources that include Stack Exchange Network

Vulnerabilities

No vulnerabilities reported

Install lock-striping

You can download it from GitHub.
You can use lock-striping like any standard Java library. Please include the the jar files in your classpath. You can also use any IDE and you can run and debug the lock-striping component as you would do with any other Java program. Best practice is to use a build tool that supports dependency management such as Maven or Gradle. For Maven installation, please refer maven.apache.org. For Gradle installation, please refer gradle.org .

Support

For any new features, suggestions and bugs create an issue on GitHub. If you have any questions check and ask questions on community page Stack Overflow .

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